1. Field of the Invention
The present invention relates to vehicle vision systems. More particularly, the present invention relates to improving position and size estimates of nearby vehicles.
2. Description of the Related Art
Vehicle vision systems include a sensor or sensors that image scenes proximate a vehicle, e.g., in front or behind the vehicle. A vehicle having a vision system will be referred to herein as the host vehicle. A sensor for a vision system may include a radar system, an infrared sensor, an optical system, and the like. In any event, the sensor produces rudimentary image data of the scene around the host vehicle. Subsequently, image-processing techniques are applied to the rudimentary image data to identify objects that are within the sensor's field of view. Since vehicle vision systems are often used in collision avoidance systems, an object within the sensor's field of view will be referred to as a target.
While vehicle vision systems can identify when a target is in front of a host vehicle, such systems usually do not provide accurate information about either the target or its movement. As such, a driver of a host vehicle may be warned of a target, or the host vehicle may automatically take evasive action, yet the target may represent no danger.
To help identify when a target is a danger, it would be beneficial to accurately know both the size and the position of the target. To do so, the edges of the target must be known. Such edge information could then be used to accurately determine the target's height, width, and position. Accurate height, width, and position information would be very useful in differentiating between different types of targets, such as sedans, SUVs, and trucks, and in accurately discriminating between collisions and near misses. Therefore, there is a need in the art for a method and apparatus that provides accurate information regarding a target's size and position. Such methods and apparatus would be particularly beneficial in vehicle vision systems in general, and in collision avoidance systems in particular.